"Environmental groups launched a complaint against Canada under the North American Free Trade Agreement Wednesday, saying the country has failed to enforce anti-pollution rules governing its vast oil sands.

In the latest move in a long-running campaign to highlight the impact of oil sands development, the submission by Environmental Defense Canada, Natural Resources Defense Council and three citizens charges that toxic tailings ponds are being allowed to leak and contaminate ground water.

The ponds store residual oil, heavy metals and other byproducts of oil sands processing in the western province of Alberta. They are subject to environmental provisions under the federal Fisheries Act, the groups said."